On Mon, Jun 17, 2019 at 09:01:33PM +0800, Chen-Yu Tsai wrote: > On Mon, Jun 17, 2019 at 7:45 PM Maxime Ripard <maxime.ripard@xxxxxxxxxxx> wrote: > > > > On Fri, Jun 14, 2019 at 10:13:20PM +0530, Jagan Teki wrote: > > > TCON TOP have clock gates for TV0, TV1, dsi and right > > > now these are register during bind call. > > > > > > Of which, dsi clock gate would required during DPHY probe > > > but same can miss to get since tcon top is not bound at > > > that time. > > > > > > To solve, this circular dependency move the clock gate > > > registration from bind to probe so-that DPHY can get the > > > dsi gate clock on time. > > > > It's not really clear to me what the circular dependency is? > > > > if you have a chain that is: > > > > tcon-top +-> DSI > > +-> D-PHY > > > > There's no loop, right? > > Looking at how the DTSI patch structures things (without going into > whether it is correct or accurate): > > The D-PHY is not part of the component graph. However it requests > the DSI gate clock from the TCON-TOP. > > The TCON-TOP driver, in its current form, only registers the clocks > it provides at component bind time. Thus the D-PHY can't successfully > probe until the TCON-TOP has been bound. > > The DSI interface requires the D-PHY to bind. It will return -EPROBE_DEFER > if it cannot request it. This in turn goes into the error path of > component_bind_all, which unbinds all previous components. > > So it's actually > > D-PHY -> TCON-TOP -> DSI > ^ | > |-------------------- > > I've not checked, but I suspect there's no possibility of having other > drivers probe (to deal with deferred probing) within component_bind_all. > Otherwise we shouldn't run into this weird circular dependency issue. > Ah, yes, that makes sense. It should be cleraer in the commit log then. Thanks! Maxime -- Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
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